How has our ability to communicate defined us as a species? Sharing information with each other has allowed humans to rise to the top of the food chain and dominate our environments. But humans aren't the only species that can communicate. Organisms as simple as bacteria can communicate, a strategy that lets them cooperate to take down creatures millions of times their own size. Fish use pheromones to warn each other about predators and find mates. Chemicals are also an effective means of communicating on land, and they've allowed insects--some of nature's smallest and most unassuming animals--to become the most populous and prolific on earth. The ability to interact stretches back billions of years and has often been one of the primary factors in a species ability to evolve and survive.